Saturday, May 28, 2011

Buffers – Sodium Bicarbonate & Beta-alanine

In the last post I explained how increased blood acidity during high intensity or anaerobic exercise causes fatigue, as the brain works to prevent blood acidity becoming too high. Today let’s look at two potential nutrition strategies to buffer the rise in acidity and enhance high intensity performance –bicarbonate loading and beta-alanine.


Sodium Bicarbonate – A powerful but short term buffering agent

One of the body’s natural systems for buffering the rise in acidity during exercise is the presence of bicarbonate in the blood. Bicarbonate is a naturally occurring substance in the blood, which reacts with the hydrogen (which is what causes acidity in the blood) to neutralise it’s acid effect. Increasing the level of bicarbonate in the blood increases blood pH (reduces acidity) prior to exercise. This allows a greater level of lactate to be produced without causing fatigue and the subsequent drop in exercise pace or intensity (due to reduced pH).

Sodium bicarbonate has been used as a sports supplement for several years now in sports requiring short, high intensity efforts (40 seconds up to 5 minutes). It can be given in several forms including capsules (such as Sodibic) and in a flavoured powder together with sodium citrate (sold as Ural, primarily used to treat urinary tract infections). But pure sodium bicarbonate is a cheap and common household product – Bicarb soda. Either way it’s taken as a single dose in the lead up to exercise.

The effect of bicarbonate on the blood pH is temporary so the timing of supplement intake is very important. It’s been used with success in track cycling, swimming, rowing and middle distance athletics events (typically 400-1500m), however it’s not beneficial in longer duration exercise which finishes with a high intensity effort (eg. sprint finishes to a cycling road race that’s been going for several hours). It can be used for maximising high intensity training (and subsequent adaptation), and for one-off competition performance in events lasting 30 seconds to 7 minutes.



How to take it & how to prevent side-effects

The optimal dose of sodium bicarb to provide a benefit to performance is around 0.3 grams per kilogram of body weight. So for a 70kg athlete that’s 0.3 X 70 = 21 grams. This is easily controlled using capsules of a know amount, or by weighing out bicarb soda powder.

There is a distinct downside to sodium bicarbonate supplementation if you’re not careful of how you take it – many athletes experience gastrointestinal problems such as bloating and diarrhoea as a side effect. This is because large amounts of sodium bicarb in the gut causes water to be drawn into the intestinal tract to dilute it. I was lecturing for cycling coaches last year and asked one participant (an ex-Olympic track cycling medallist) about his experience bicarb loading. His response – “I’d get to the starting line not knowing if I was going to s%&t my pants or not!”

However recent research has shed some light on the most effective protocols for bicarb loading, to maximise the benefits and minimise side effects. Just this month a new study from the Australian Institute of Sport was published, comparing eight different methods of bicarb loading. Sodium bicarb in capsule or powder form (bicarb soda) worked better than Ural, both for raising pH before exercise and for minimising side effects. Ideally it should be taken around three hours before competition, and consumed with plenty of water (around 7mL per kilogram of body weight, or 490mL for a 70kg athlete). Having a high carbohydrate meal or snack at the same time also reduced the side effects.

Finally, the timing of bicarb loading is also important. Research shows that the maximum effect of bicarb loading on blood pH occurs between 2-3 hours after consumption, so taking bicarb 2-3 hours before a training session or competition will achieve the maximum benefit to performance.



Beta-alanine

As described in the previous post, beta–alanine is one half of the carnosine molecule, which in the muscle acts as a buffer before the hydrogen ions are released into the blood. Beta-alanine is the limiting factor for the body to produce carnosine, so beta-alanine supplements increase the body’s carnosine stores in the muscle.

Unlike bicarbonate where a single dose is used a couple of hours before training or competition, beta-alanine slowly increases carnosine stores over a prolonged period of time. Carnosine stores can also remain elevated for a few weeks after supplementation is ceased. The more beta-alanine given, the faster the increase in muscle carnosine.

As beta-alanine has only been widely known in the last five or so years, there is still only limited research about which sports benefit from its use. Certainly the sports that benefit from bicarbonate loading will probably also benefit from beta-alanine supplementation. The other benefit may be for longer races where short bursts of anaerobic exercise make the difference between winning and losing, such as mountain biking, adventure racing and road cycling.

How to take it & how to prevent side-effects

Recommended loading protocols for beta-alanine state that 3000-5000mg a day should be consumed to maximise carnosine stores over about 8 weeks. However there’s a limit to the amount of beta-alanine you can consume in one go, due to the often severe side effects experienced when taking large doses at once. The side effects are known as paraesthesia (flushing or pins and needles) and occur when blood beta-alanine levels become too high. This usually occurs with doses of more than about 800mg at a time.

Beta-alanine is available commercially in Australia in both powder and capsule form. The powder can be simply put on a teaspoon in your mouth and washed down with water. Some (but not all) capsules provide a slow release of beta-alanine, allowing you to consume larger doses (around 1500-2000mg in one go) without side effects. Taking beta-alanine (powder or capsules) just after a meal also helps to minimise paraesthesia by slowing down stomach emptying and the absorption into the blood. These strategies allow you to take say 3 doses of 1600mg across the day, much more convenient than 6 doses of 800mg.



Combining Bicarb Loading and Beta-alanine

In the last couple of years researchers have started to investigate whether the effects of bicarb loading and beta-alanine are additive (ie. do you get an even greater benefit from taking both). Theoretically there is no reason why this shouldn’t be the case, since bicarb buffers in the blood and beta-alanine buffers in the muscle.

Only one study to date has been published that looks at this. However it used a method which is not preferred because it doesn’t simulate typical sports. They found that bicarb loading in addition to beta-alanine supplementation resulted in a 4.1% improvement in Time To Exhaustion at a fixed pace of cycling, however there was a 7% probability that this could have occurred by chance.

The Australian Institute of Sport commenced a study last year looking at the benefits of their swimmers taking both supplements together, however the results have not been published as yet.

Summary

Bicarbonate loading increases the pH (reduces aciditiy) in the blood. This allows athletes to produce more blood lactate without a fall in pH (and the subsequent fatigue and reduction in pace). Bicarb can be taken in capsules or in powder form (as bicarb soda dissolved in water). The optimal protocol to is to consume 0.3g/kg body weight with 7mL/kg water and a high carb meal, about 2-3 hours prior to exercise. This maximises the benefits whilst minimising the side effects.

Beta-alanine supplementation increases the store of carnosine in the muscle. Carnoisine buffers against rising acidity in the muscle, therefore delaying the rise in blood acidity and enhancing high intensity exercise performance. Beta-alanine can be taken in powder form or capsules. To get the maximum benefit take 3000-5000mg a day (split into doses of 800mg, or 1600mg of slow release capsules) for around eight weeks prior to competition. Taking your beta-alanine just after a meal also helps to minimise side effects.

Finally, the jury is still out as to whether the combination of bicarb loading and beta-alanine will provide even greater benefit compared to one or the other. Theoretically it should, however we await research results for this to be confirmed.

5 comments:

  1. Could you explain how the bicarb gets absorbed? I like the idea, but I can't think why it wouldn't just act as a buffer in the stomach (which might then have a negative impact on digestion). Thanks.

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  2. Apologies for the very delayed reply, didn't have email alerts enabled! Not sure of the exact mechanism of absorption of bicarb through the intestinal wall, but rest assured plenty of research shows an increased blood bicarbonate (and increase in pH/reduction in acidity) as a result.

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  3. No problem! I like the idea, but I'm worried that consuming bicarb would first raise the pH in the stomach, which might hinder protein digestion (since pepsinogen is converted to pepsin only at low pH). Then, when the contents of the stomach enter the intestine it's once again the low pH that triggers the release of secretin, which triggers the release of bicarb (neutralizing stomach HCl, bringing pH back to about 7 and allowing intestinal enzymes to function)... so maybe adding bicarb earlier would just mean releasing less later, and this might lead to higher levels in the blood? But then I'd be curious to know why the increased pH wouldn't be immediately buffered by changing respiration rates...

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    1. Hi Patrick, I suspect bicarb probably does have a small impact on stomach pH, not sure about whether or not it's enough to affect pepsinogen conversion. But given bicarb loading is only used in the couple of hours prior to exercise I can't imagine it would be a problem since there's no specific benefit to consuming protein in that time anyway (especially for short, high intensity sports).

      As for the affect of respiration on maintaining pH homeostasis, I'm assuming it must simply be that the level of bicarb ingested is sufficient to overcome this effect. I can't add images to these comments, but in the AIS paper all bicarb loading protocols significantly raised blood pH (from baseline of ~7.41 to 7.45-7.50 for the four hour duration of the study. The pH of the placebo group over the same period was 7.38-7.40 and was statistically significantly lower than bicarb loading protocols.

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    2. Hey! Not sure if this is still up to date but I found all this to be extremely interesting and am curious to give either supplement a try for my senior year track season in high school.
      I am a MD runner who focuses on the 800m. I am running 2:02 and hope to get down to a 1:56 by the end of the season.
      I've down plenty of research on both Sodium Bicarbonate and Beta Alaine. Sodium Bicarbonate seems to be fairly straightforward, though risky, in terms of its use and benefits. However, my understandings on Beta Alaine have never been as clear as I would wish. Some say to take it as daily supplement and have a "loading phase". Others suggest that you only take it the day of the workout/competition in dosages of which you mentioned.

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